QGIS print composer, export as image, rest ESRI raster as basemap

Question

I am trying to export an image from the print composer using this layer [ESRI rest layer][1] as a basemap. http://services.arcgisonline.com/arcgis/rest/services/ESRI_Imagery_World_2D/MapServer

I connected to the layer using the python plugin and this tutorial. http://hub.qgis.org/wiki/quantum-gis/Arcgis_rest

When I go to export my map made in print composer as an image the basemap doesn't show up and I get a grey hatching with 'no map data' on it. It worked a few times and then quit for some reason. The print composer version looks great but the only way I can export seems to either screen grab or save the maps as images and then add through the print composer.

Any thoughts on how to solve this issue? It worked so I imagine i've twiddled something and need to untwiddle it to resolve the issue.

Answer 1

In Print Composer, go to the Composition tab in the right-hand menu. Scroll down to Export Settings. Check what your export resolution is set at. Chances are, it is a higher resolution than what is displayed as a preview in print composer. Try setting this to 300 dpi, or lower.

If the export resolution is too high, it seems QGIS will send a request to the raster server at a different scale than what is shown on the preview. I have particularly seen this when accessing maps where there are place name labels that get very small on export. I've found that changing the export resolution sometimes helps, as long as you don't go too low where the map isn't as crisp.

I am guessing that the image request sent by QGIS when you export could be for a zoom level that is not available from the server, resulting in the 'no map data' error.

Answer 2

Since version 2.14, you have the option to add ArcGis MapServer Layer directly from the "Add Layer" menu.

The ArcGIS REST API connector plugin - which I think is what you referred to in the now removed url - works for vectors.

The issue you describes seems more like a general connection issue where QGIS can't load the tiles from source, either due to connectivity issues, or tiling issues.

Furthermore, there are other ways of adding a global image, using the QuickMapService plugin, you can load many common world rasters from ESRI (Bing), Google, and others.